>>> well, shifting gears now, president obama and about 120 other world leaders gather here in new york today for the start of this year's u.n. general assembly. as iran's mahmoud ahmadinejad left tehran for the meeting, he promised a debate on the crisis in syria. iran is accused of helping syrian president bashar al assad's brutal crackdown on rebels. >>> and in syria, an explosion near the four seasons hotel near damascus has killed at least one person. a bomb hid inside a bag blew up as they held a rare meeting inside the capital city. the assad regime apparently allowed the meeting to bolster its claim of being open to political reform despite the deadly assaults on rebels. >>> despair at the national zoo. just a week after its surprise birth, a giant panda cub has died. zookeepers were alerted yesterday morning when the cub's mother made a distress call. the staff managed to get the cub out and administer cpr, but it was too late. the cub was conceived through artificial insemination after its mom had five failed pregnancies. preliminary findings on the cause of death are expected